How our site in Tennesse is helping to realise the Sustainability 2017 Vision through its reduction in the consumption of water and raw materials...
The Johnson Matthey site in Sevierville, Tennessee produces – among other things – sponge nickel catalysts which have applications in the pharmaceutical industry as well as in a wide range of other chemical processes. A project to reduce the use of critical raw materials, which began in 2008, is now bearing fruit. The impressive reductions and process improvements achieved have earned the site Johnson Matthey's Award for Sustainable Operations or Supply Chain for 2011/12.
Two ingredients constitute the critical raw materials in the production of the sponge nickel product: sodium hydroxide, in the form of a 50% caustic solution, and water. They may be added multiple times (for 'multiple boil' products) over the course of the batch.
The price of caustic was increasing substantially in late 2008 and analysis of the process showed that there was a real opportunity to reduce the amount used and save costs. There was also a problem in the capacity of the site to concentrate the sodium aluminate that was produced as a byproduct stream, which was creating a bottleneck in the process. So there was also a clear need to make the operation more sustainable.
Several Steps to Success
The first step in the raw material reduction project – introduced at the end of 2008 – was to decrease the use of wash water by increasing the amount of recycled water used from one batch to the next. A temporary tank was installed and trials were performed to ensure that the recycled wash water didn't have any negative impact.
The following step was to tackle the recycling of sodium hydroxide. Recycling efforts were targeted on products which had multiple additions of sodium hydroxide. In January 2009 production trials were conducted using the existing tanks and connections. But the site team knew that the real results lay ahead and in late 2010, the recycled caustic system and the recycled water system were upgraded and automated. Permanent process water tanks and a separate recycled sodium hydroxide delivery system were installed, together with an upgraded sodium hydroxide delivery system.
The question of multiple boils was next to be reviewed as processes were optimised. The team found that the number of sodium hydroxide boils could be cut by half for one product, significantly reducing the amount of manual operation.
It was not all straightforward. Johnson Matthey Tennessee is not a large site and so one problem to overcome was how to design the automated system within the limited space available. A Kaizen – or continuous improvement – team was set up to review and streamline the manufacturing floor space. The way forward was to clear out a warehouse to make room for crucibles, drums and products that were in current use which in turn freed up space on the manufacturing floor.
This meant that larger process water tanks could be installed, which opened up the possibility of operating the processes with just one tank, not two. So the spare tank was converted into a recycled sodium hydroxide storage tank. Installation was completed in sections to minimise production downtime.
The project also helped reduce the use of natural gas to run the boiler. Steam from the boiler is used to concentrate the byproduct liquors and now that caustic recycling has reduced the volume of the byproduct stream, use of steam from the boiler and natural gas has been reduced.
There was active involvement in the project across the functions. The Kaizen team was made up of almost every major functional group and once the project for the new installations was formally approved, another cross functional project team – consisting of operations, engineering, Environment, Health and Safety, development and maintenance – was established.
So What is the Outcome of the Project to Date?
On the critical raw materials of sodium hydroxide and water, much has been achieved. Caustic usage for multiple boil products has been markedly reduced; so too has the use of water. Standard single boil products have also benefited, thanks to the extra tank capacity for storing and recycling the water from one batch to the next. Importantly, the new water and caustic recycling processes have eliminated the bottleneck at the point where the sodium aluminate byproduct is produced.
The figures say it all. The removal of the bottleneck, for a start, has increased capacity by around a third. In the 2011/12 financial year, process water usage in production was reduced by some 1.49 million US gallons.
The use of sodium hydroxide also reduced by over 125,000 US gallons. The reductions in water, sodium hydroxide and natural gas equate to a total savings of $370,000 in the 2011/12 financial year. Going back further to the start of the Critical Raw Material Reduction project, there has been a reduction of process water of 4.8 million US gallons (achieving savings of around $20k) and a reduction of sodium hydroxide use of 413,000 US gallons (savings of around $630k).
The project is helping to realise the Sustainability 2017 Vision through its reduction in the consumption of water and raw materials. It has also helped make the site more profitable and its products more competitive in the marketplace. This is what 'sustainable operations' is all about.